Various commercially available endoscopes and steerable catheters exist for introducing a variety of surgical tools, fluids, and other materials such as radiographic contrast materials, angioplasty balloons, fiber optic scopes, laser lights, and cutting instruments into the vessels, cavities, or tissue of a human body. Also, various techniques and systems have been developed for guiding or steering the catheters or endoscopes in body vessels or cavities for use with these tools, fluids, and other materials. Therapeutic or diagnostic treatments may be made by inserting surgical instruments or fluid through a working channel or lumen of a catheter.
Catheters conventionally include a conduit or flexible tube for inserting into a cavity, duct, or vessel of the human body to allow fluids to pass therethrough or to allow instruments to be inserted through the tube. Catheters also have been developed with steering mechanisms to guide or manipulate the catheter such as seen in U.S. Pat. No. 5,199,950 by Schmitt et al. titled "Medical Instrument." Endoscopes are generally tools used to view within a portion of the anatomy through an open end of a tube. Flexible endoscopes have been constructed for use within "tube-like" portions or cavities of the anatomy (e.g., arteries, ureters, common bile duct). Endoscopes have been designed for the user to look directly through an objective lens or in conjunction with video cameras attached remotely to the scope for viewing a portion of the human body. Rod lens systems also have been used with some endoscopes to view images. In other endoscopes, the image is gathered at the distal end by a lens and transferred to a proximal objective lens using fiber optic bundles.
During use in medical procedures, endoscopes and steerable catheters are exposed to various viruses, bacteria, and harmful disease carrying media. These viruses and bacteria can be trapped in the endoscope or steerable catheter, particularly in lumens and transferred to subsequent patients or users. During use of these medical devices, microbes have also been trapped inside patient materials that remain in the endoscopes and become coated with lubricants and various organic materials in the endoscope. If not effectively eliminated, these materials can and have been transferred to other patients or medical personnel through subsequent use of the endoscope or steerable catheter. In the human body, enzymes and digestive processes work to release these internally trapped microbes from the lubricant coatings. These harmful microbes can infect the subsequent patients or medical personnel with dangerous or deadly diseases.
Sterilization methods have been employed on reusable medical devices, including various endoscopes and steerable catheters, in an attempt to disinfect and eliminate viruses and bacteria for subsequent use of the devices. For example, glutaraldehyde has been used to treat reusable endoscopes. Also, heat sterilization and other chemical disinfection have been employed to attempt to sterilize internally contaminated medical devices. Some endoscopes and steerable catheters contain very small and narrow working channels or lumens for performing intricate medical procedures. These small or narrow working channels or lumens are difficult to clean and sterilize. Further, research has shown that, in spite of attempts to sterilize endoscopes, endoscope lubricants can shield viruses, including HIV, from high-level disinfection. Disease transmissions have been documented for endoscopes used in diagnostic and surgical procedures even after treatment with chemicals such as glutaraldehyde. The instances of epidemics of various diseases, including new and old diseases, are rising due to the increasing density of human population and frequency of human contact. At the same time, the effectiveness of certain antibiotics is diminishing and the numbers of individuals with increased susceptibility to disease is on the increase. Technological advances have also increased the frequency of use of medical instruments which are difficult to clean, yet are not disposable. These factors have produced an environment where the likelihood of infection caused by passing disease causing viruses, bacteria, or other matter is rapidly increasing.
In addition to the problem of infection and transmission of disease, prior endoscopes and catheters by virtue of their design and materials have been intended for prolonged, repeated use. The precision of manipulation and movement in endoscopes and steerable catheters is essential for conducting the complicated medical procedures and diagnostics generally employed by such devices. Some repeated use endoscopes and steerable catheters have contained steering mechanisms to manipulate the endoscopes within the human body. These mechanisms have been complicated and required precision calibration. Further, these devices have also had to withstand sterilization with heat or chemicals. To accomplish these objectives, reusable endoscopes and steerable catheters have been made of steel or other durable metals which are costly.
To maintain integrity and precision, endoscopes and steerable catheters have generally been designed as intended for repeated, prolonged use. In spite of being designed for repeated use, however, these scopes such as laparoscopes, require replacement much more frequently than other visualization equipment such as cameras or light sources. A typical replacement cycle is one to two years. In high volume surgery centers, some scopes require replacement after a few weeks or months due to damage from mishandling or dropping. Repairing these endoscopes is also costly. The requirement of sterilization also adds additional cost to each medical procedure requiring additional chemicals and equipment.
Limited attempts have been made to provide a detachable reusable endoscope. One repeated use detachable-end endoscope with a detachable flexible shaft is described in U.S. Pat. No. 4,911,148 by Sosnowski et al. titled "Deflectable-End Endoscope With Detachable Flexible Shaft." This patent describes a flexible shaft assembly which connects to a handle subassembly to form an endoscope. The handle subassembly includes a hollow female bayonet connector which couples with a male connector in the shaft subassembly. The endoscope described in U.S. Pat. No. 4,911,148 by Sosnowski has a central opening extending from a proximal end to the distal end of the endoscope. A lens is positioned within the opening to provide appropriate magnification for an operator to manually view the distal end of the endoscope. This endoscope is also intended for reuse as both the shaft subassembly and handle subassembly are provided with watertight seals to prevent a compromise of internal components resulting from usage and sterilizations. The shaft subassembly, however, as described above, has some of the sterilization failures of previous technology and provides an awkward and inefficient manner for viewing the distal end of the endoscope.
In addition to the issues of disease transmission and disposability, numerous endoscopes have been designed which are bulky or difficult to use, requiring numerous hands or personnel. Hand-held catheters have been developed to provide the control and manipulation of the catheter for simultaneous use with surgical tools, fiber optic scopes, and fluids needed for medical operations, such as in U.S. Pat. No. 5,342,299 by Snoke et al. titled "Steerable Catheter." Many medical procedures, however, require passage of relatively straight instruments into the human body at an angle difficult to actuate relative to the position of the portion of the medical device in the medical practitioner's hand.
As stated, none of the prior catheter or endoscope systems utilized fiber optic imaging systems to view within a human body. These systems required the use of an endoscope or catheter in conjunction with an external camera for transmitting images from within a human body to an external monitor. These external cameras occupied limited space in the operating or examination rooms and were susceptible to breakage or contamination. Still further, these cameras needed to be designed to withstand required direct sterilization.
Charged-coupled devices ("CCD's") have been proposed for use with endoscopes allowing direct image capture at the distal tip of an endoscope. Such systems conventionally place a camera chip at the distal end of a scope such as a laparoscope are referred to as a "chip-on-a-stick." These chip-on-a-stick devices are used in conjunction with an external camera connected to the scope by a cable. These chip-on-a-stick devices have several problems associated with them. For example, the scope may become contaminated during a procedure and sterilization often cannot be adequately performed on the device because of the presence of the CCD chip. This CCD chip also makes the scope somewhat expensive, especially where contamination occurs and sterilization is not possible without damaging the chip.
In chip-on-a-stick systems, the chip-on-a-stick generally would not be susceptible to sterilization at the tip of the endoscope because the camera chip is positioned on or around the tip. These external cameras also require space in shipping and storage. Prior endoscopes or steerable catheters which utilized fiber optic technology also often had an external focus mechanism associated with the external camera. This would require the practitioner to look or reach away from the area of the procedure to focus the image being viewed within the human body.